package com.yuhan.common.utils;

import org.apache.commons.codec.binary.Base64;

import javax.crypto.Cipher;
import java.security.*;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.HashMap;
import java.util.Map;

/**
 * @description: RSA工具类
 * @author: hejing
 * @create: 2019/8/29
 **/
public class RSAUtils {
    public static final String KEY_ALGORITHM = "RSA";
    public static final String SIGNATURE_ALGORITHM = "MD5withRSA";
    private static final String PUBLIC_KEY = "RSAPublicKey";
    private static final String PRIVATE_KEY = "RSAPrivateKey";

    private static String PUBLIC_KEY_VALUE = "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDueTFeS9CANE8iMxlXqgSqRqQiBSb75RxayJV0bkH9tYrGuAK4UAbuu8iur0HzrAZShEmtaQ/S64yHxvCBtkauzN1QqUopdo/0TEdRI5HLGkbEvxLw7/SDQccnY41PFujkzc1aVaVBWJ33SopeO4zR8pLA5V4o9KMp+XE/a7sVTQIDAQAB";

    public static byte[] decryptBASE64(String key) {
        return Base64.decodeBase64(key);
    }

    public static String encryptBASE64(byte[] bytes) {
        return Base64.encodeBase64String(bytes);
    }

    public static String sign(byte[] data, String privateKey) throws Exception {
        // 解密由base64编码的私钥
        byte[] keyBytes = decryptBASE64(privateKey);
        // 构造PKCS8EncodedKeySpec对象
        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
        // KEY_ALGORITHM 指定的加密算法
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        // 取私钥匙对象
        PrivateKey priKey = keyFactory.generatePrivate(pkcs8KeySpec);
        // 用私钥对信息生成数字签名
        Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
        signature.initSign(priKey);
        signature.update(data);
        return encryptBASE64(signature.sign());
    }

    public static boolean verify(byte[] data, String publicKey, String sign) throws Exception {
        // 解密由base64编码的公钥
        byte[] keyBytes = decryptBASE64(publicKey);
        // 构造X509EncodedKeySpec对象
        X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
        // KEY_ALGORITHM 指定的加密算法
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        // 取公钥匙对象
        PublicKey pubKey = keyFactory.generatePublic(keySpec);
        Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
        signature.initVerify(pubKey);
        signature.update(data);
        // 验证签名是否正常
        return signature.verify(decryptBASE64(sign));
    }

    public static byte[] decryptByPrivateKey(byte[] data, String key) throws Exception {
        // 对密钥解密
        byte[] keyBytes = decryptBASE64(key);
        // 取得私钥
        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key privateKey = keyFactory.generatePrivate(pkcs8KeySpec);
        // 对数据解密
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
        cipher.init(Cipher.DECRYPT_MODE, privateKey);
        return cipher.doFinal(data);
    }

    public static byte[] decryptByPrivateKey(String data, String key) throws Exception {
        return decryptByPrivateKey(decryptBASE64(data), key);
    }

    public static byte[] decryptByPublicKey(byte[] data, String key) throws Exception {
        // 对密钥解密
        byte[] keyBytes = decryptBASE64(key);
        // 取得公钥
        X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key publicKey = keyFactory.generatePublic(x509KeySpec);
        // 对数据解密
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
        cipher.init(Cipher.DECRYPT_MODE, publicKey);
        return cipher.doFinal(data);
    }

    public static byte[] encryptByPublicKey(String data, String key) throws Exception {
        // 对公钥解密
        byte[] keyBytes = decryptBASE64(key);
        // 取得公钥
        X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key publicKey = keyFactory.generatePublic(x509KeySpec);
        // 对数据加密
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
        cipher.init(Cipher.ENCRYPT_MODE, publicKey);
        return cipher.doFinal(data.getBytes());
    }

    public static byte[] encryptByPrivateKey(byte[] data, String key) throws Exception {
        // 对密钥解密
        byte[] keyBytes = decryptBASE64(key);
        // 取得私钥
        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key privateKey = keyFactory.generatePrivate(pkcs8KeySpec);
        // 对数据加密
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
        cipher.init(Cipher.ENCRYPT_MODE, privateKey);
        return cipher.doFinal(data);
    }

    public static String getPrivateKey(Map<String, Key> keyMap) throws Exception {
        Key key = (Key) keyMap.get(PRIVATE_KEY);
        return encryptBASE64(key.getEncoded());
    }

    public static String getPublicKey(Map<String, Key> keyMap) throws Exception {
        Key key = keyMap.get(PUBLIC_KEY);
        return encryptBASE64(key.getEncoded());
    }

    public static Map<String, Key> initKey() throws Exception {
        KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance(KEY_ALGORITHM);
        keyPairGen.initialize(1024);
        KeyPair keyPair = keyPairGen.generateKeyPair();
        Map<String, Key> keyMap = new HashMap(2);
        keyMap.put(PUBLIC_KEY, keyPair.getPublic());
        // 公钥
        keyMap.put(PRIVATE_KEY, keyPair.getPrivate());
        // 私钥
        return keyMap;
    }

    public static void main(String[] args) throws Exception {
        Map<String, Key> map1 = RSAUtils.initKey();
        String pub = RSAUtils.getPublicKey(map1);
        String pri = RSAUtils.getPrivateKey(map1);
        System.out.println(pub);
        System.out.println(pri);
        String pwd = "123456";
//        byte[] bytes = RSAUtils.encryptByPublicKey(pwd, PUBLIC_KEY_VALUE);
//        String encryptBASE64Str = RSAUtils.encryptBASE64(bytes);
//        System.out.println(encryptBASE64Str);
    }

}